Oral appliance



FIG. 1 is a rear view of an oral appliance;

FIG. 2 is an enlarged right side view thereof;

FIG. 3 is an enlarged left side view thereof;

FIG. 4 is a front view thereof;

FIG. 5 is a top view thereof;

FIG. 6 is a bottom view thereof; and,

FIG. 7 is a rear bottom perspective view thereof. 

CLAIM The ornamental design for an oral appliance, as shown and described. 